The present invention relates to power tools and, more particularly, to a leveling device that indicates when the power tool is in a horizontal or vertical plane.
In various types of power tools, especially drilling tools, it is desirable to know when the tool is in a horizontal or vertical plane. This is particularly useful when drilling holes for hanging doors or the like when it is desirable to have holes which are in plane with horizontal.
Bubble type of levels have been utilized in power tools. However, these types of leveling devices have various shortcomings. While the bubble level works satisfactorily for horizontal applications, it is still burdensome on the user to view the bubble in between the lines. Ordinarily, these bubble types of levels are not conducive for vertical drilling. Also, due to the vibration of the tool, frothing occurs inside the level, rendering the bubble level useless in many applications.
Another type of measuring device utilizes a simple pendulum with a rigid straight bar connecting the pivot point with a hanging weight together with a cross bar mounted at ninety (90°) degrees to a vertical bar. The cross bar can be disposed on either side of the pivot point when the pivot level is hung and the weight achieves equilibrium, the cross bar will be positioned in a horizontal plane. Accordingly, the ends may be aligned with two notches on a carrier board to align the board to the horizontal and thus measure the horizontal plane.
Both of these devices require the user to get an accurate view during drilling to maintain the plane of the power tool. Also, while these types of devices may be satisfactory for horizontal planes, they are not particularly useful when used in a vertical drilling arrangement.
Accordingly, it is an object of the present invention to provide a user with an easy to use leveling device. The device indicates to the user, usually by an illuminated light, that horizontal or vertical planes have been achieved. The present invention enables the user to readily establish visual contact to indicate that a desired plane has been achieved.
According to a first embodiment of the present invention, a mechanism for determining if a power tool is in a horizontal or vertical plane comprises a housing with a cavity in the housing. A rotating member is positioned within the housing. The rotating member moves in the cavity such that the rotating member seeks an equilibrium position which corresponds to a horizontal or vertical plane. Electrical contacts are coupled with the rotating member such that the electrical contacts only complete an electrical circuit when the rotating member is in the equilibrium position. An indicator is electrically coupled with the electrical contacts to indicate to the user when the mechanism is in an equilibrium position. A power source is electrically coupled with the electrical contacts and the indicator to energize the indicator when the circuit is complete. The rotating member may be fixed for rotation about a central axis in a cylindrical cavity in the housing. Here, the rotating member includes a biased electrical contact. The electrical contacts include a pair of annular members coupled with the housing. Each annular member includes electrical contact portions spaced ninety (90°) degrees from one another. Thus, as the rotating member reaches the equilibrium position, the rotating members biased electrical member contacts the annular ring electrical contact portions to complete the circuit and activating the indicator. Alternatively, the rotating member could be manufactured from an electrical conductive material. Here, the rotating member is cylindrical and has at least one projecting member. The electrical contacts include a biased member to electrically contact the at least one projecting member when the cylindrical rotating member is in the equilibrium position. An axle projects through the cylindrical rotating member to complete the circuit. Alternatively, the cavity may be defined by a pair of opposing conductive conical members acting as the electrical contacts. Here, the rotating member includes a pair of conductive balls. The opposing conductive cylindrical members are separated by a non-conductive membrane. The membrane includes apertures positioned at ninety (90°) degrees apart from one another about a circle. The balls contact one another through the apertures in the membrane when the balls are in the equilibrium position to complete the circuit and activate the indicator.
In accordance with a second embodiment of the present invention, a power tool comprises a housing with a motor within the housing. The motor is coupled with an output. An activation member is coupled with a power source which, in turn, is coupled with the motor. The activation member is activated which, in turn, energizes the motor to drive the output. A leveling mechanism is coupled with the housing. The leveling mechanism comprises a housing with a cavity in the housing. A rotating member is positioned within the housing. The rotating member moves in the cavity such that the rotating member seeks an equilibrium position which corresponds to a horizontal or vertical plane. Electrical contacts are coupled with the rotating member such that the electrical contacts only complete an electrical circuit when the rotating member is in the equilibrium position. An indicator is electrically coupled with the electrical contacts to indicate to the user when the mechanism is in an equilibrium position. A power source is electrically coupled with the electrical contacts and the indicator to energize the indicator when the circuit is complete. The rotating member may be fixed for rotation about a central axis in a cylindrical cavity in the housing. Here, the rotating member includes a biased electrical contact. The electrical contacts include a pair of annular members coupled with the housing. Each annular member includes electrical contact portions spaced ninety (90°) degrees from one another. Thus, as the rotating member reaches the equilibrium position, the rotating member's biased electrical member contacts the annular ring electrical contact portions to complete the circuit and activate the indicator. Alternatively, the rotating member could be manufactured from an electrical conductive material. Here, the rotating member is cylindrical and has at least one projecting member. The electrical contacts include a biased member to electrically contact the at least one projecting member when the cylindrical rotating member is in the equilibrium position. An axle projects through the cylindrical rotating member to complete the circuit. Alternatively, the cavity may be defined by a pair of opposing conductive conical members acting as the electrical contacts. Here, the rotating member includes a pair of conductive balls. The opposing conductive cylindrical members are separated by a non-conductive membrane. The membrane includes apertures positioned at ninety (90°) degrees apart from one another about a circle. The balls contact one another through the apertures in the membrane when the balls are in the equilibrium position to complete the circuit and activate the indicator.
Additional objects and advantages of the present invention will become apparent from the detailed description of the preferred embodiment, and the appended claims and accompanying drawings, or may be learned by practice of the invention.